Stabilization of liquid reaction products of diborane and olefin hydrocarbons



June 13, 1961 H. STANGE 2,988,570

STABILIZATION OF LIQUID REACTION PRODUCTS OF DIBORANE AND OLEFIN HYDROCARBONS Filed May 15, 1956 C FOR IO MIN.

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ATTORNE Y6 United States- Patent z 988 510 STABILIZATION 0F LI U1D REACTION PROD- gggg 0F DIBORANE AND OLEFIN HYDROCAR- Patented June 13, 1961 2 bottomof the reactor. Hydrogen and propylene at the rate of 640 and 80 ml. per minute respectively are mixed in one feed line before entering the reaction zone. Hydrogen and diborane at the rate of 160 and 800 ml. per

5 minute respectively are mixed in a separate feed line. Hugo zz f g g? gg'kfi figi g gi g The feed stream containing the propylene is discharged mmfion of Virginia pm through a fritted disc at the top of the heated zone of the Filed May 5 95 s 5 5 reactor. The stream containing the diborane is (118- 2 Cl i ((31, 260-6065) charged at the top of the heated reaction zone. A gas 10 sampler is located at the reactor exit in order to sample This invention relates to the stabilization of liquid borothe gaseous product before it is condensed. hydrocarbons produced by reacting diborane and an ole- The gases, including the reaction products, are passed fin hydrocarbon having 2 to 4 carbon atoms. through a trap at room temperature, a spiral trap cooled The production of liquid borohydrocarbons has been to -78 C., and finally through a Nujol safety vent. A previously proposed by the reaction of diborane and undense white fog is observed after one minute in the trap saturated hydrocarbons in the gaseous phase and in adat room temperature. The exit gases are further passed mixture with an inert diluent gas at temperatures elevated for a 10 minute period through ethyl alcohol in a flask by direct or indirect heat exchange. Such liquid boroconnected to a water-cooled condenser and then through hydrocarbons have high heats of combustion and are usea trap containing ethyl alcohol cooled to --78 C. The ful as high energy fuels when burned with air, for exunreacted gases are released through a Nujol safety vent. ample, as described in application Serial No. 533,944, After the reaction is terminated, the liquid products filed September 13, 1955, in the names of Earl A. Weilcollected in the trap cooled to --78 C. are allowed to muenster and Joel A. Zaslowsky. In addition to having warm to room temperature and the volatile gases allowed high heats of combustion, however, high energy fuels to escape through a Nujol safety vent. should becharacterized by, for example, low vapor pres- In a second run, the reactor is packed with a 11-41- inch sure, low viscosity, slight tendency to be pyrophoric, low by inch protruded nickel packing. toxicity, low freezing point and good storage stability. The pertinent data with respect to these two runs are Although the liquid borohydrocarbons produced by the set out in Table I below.

i TABLE I Hz/BgH. caHq/Hi Overall Ratio 0. Conver- Wt. of Boronin Time of Run mL/mln. rnL/mln. Hanan cin Temp. sion, product, Product, Run, percent 5:. percent min.

reaction of diborane and unsaturated hydrocarbons de- 4 Part 2 scribed above have satisfactory storage stability, it has 0 The liquid products of Part 1 are then stabilized dietitians?attained? 3.122233%; The a diborane and olefin hydrocarbons having from 2 to 4 carbottomed flask equlpped with a vacuum stop-cock and bon atoms, for example, ethylene, propylene and butylen nected t a methanol-coole d reflux condenser. The can be further stabilized with respect to vapor pressure 45 methfnol I clrculatfid A U'traP cooled without undue change in other properties by heat treat- Placed m Senes with condensen All 011 ment under particular conditions of temperature and time. bath held F constant temperature 15 q heat Source- Thus, according to the method of this invention, liquid Approxlmately 8 a) of h llquld P breaction products of diborane and olefin hydrocarbons milled in 1 of Part 1 is introduced into the read-i011 having 2 to 4 carbon atoms are stabilized with respect to flask in all inert ph The flask and c s are vapor pressure by heating such reaction products at a cooled to 196 C. before attaching the flask'to the rest temperature of 100 to 130 C. for from 10 to 40 minutes. of the system which has previously been purged with nitro- Ih invention is further illustrated y the wing gen. The oil bath at 100 c. is raised slowly around the p ,flask after the flask has warmed to room temperature. EXAMPLE I After 10 minutes the bath is removed and the flask is Part I allowed to cool in the air to room temperature. The flask and its contents are cooled to *-196 C. before it is i wgg g g ggi z zgi ggig gfiz giggg z g f detached from the system in an inert-atmosphere hon.- ployed comprises an elongated jacketed reaction chamber remammg, m the macho k 15 having a longitudinally situated heating coil in the center sub ected to stability and other testing, the results of wh ch thereof. The heating coil and jacket are connected in are set out In Table H behw and m the accompanymg series and mineral oil at 198202 C. is circulated through figure together with the result tests 011 other P i the system. The temperature inside the reactor is measof liq Products of Part 1 slmllafly heat treated under ured by a thermocouple located in a glass well near the the temperature and time conditions set out in Table H.

TABLE 11'. Mas's srno'raa or PRoPYLENn-nmonm anao'rrou rnonuo'rs 1 Propyldlboranes Penta- PNQYI' Propyl Deca Propyl- Dlpropyl Trig;- Product Fmm. borsns g diborane borane doeaceapyl Run Treatment (9) 23 borane borane borana Untreatiadi--- in. 100 0.101 30 3004 1.40 15.35 302 0. 41 1. 111 1.22 0. s2 0. 21 ui tsmd. 10.11 4. 43 18.35 1.30 1.10 0.02 0.11 0.013 115 3. r01 30 0.02 a 30 1s. 30 1. 00 2. 04 a 18 0. 32 0.11 m

1 All spectra were resolved to 18.35 tor the major pentaborane(9) of .0).

The stability studies are carried out by introducing a 4 ml. sample into a 10 ml. stainless steel Hoke cylinder .The pressure rise ,over various periods of time is observed andreeorded.

A measure of the stability of the non-volatile portion of the propylene-diborane reaction product is its change in pressure with time. As shown in the accompanying figure, the stability of the products increases markedly with heat treatment and particularly stable products are obtained by heat treatments at 115 C. for 30 minutes.

According to the mass spectrometric data presented in Table II, the heat treatment increases slightly the concentration of higher boranes and their propyl derivatives.

Although the heat-treatment process of this invention has been described with respect to the particular diboranepropylene reaction products of Example I, the process of this invention is applicable to such reaction products produced according to less limited ranges of reaction conditions. V For example, the temperatures employed may lange from about 100 C. to 250 C. The relative amounts of diborane and olefine hydrocarbons used can be varied widely, the molar ratio of diborane to olefin hydrocarbon being within the range from 0.5 :1 to 10:1. The amounts of diluent gas such as hydrogen, nitrogen, argon, or mixtures thereof, can also be varied widely, the amount so. introduced in practice being dependent upon the amound of diluent required to efiect essential mixing and heat transfer necessary for any particular mode of operation. In general, the gases entering the reaction system (diborane, olefin hydrocarbon and diluent gas) will be composed of from about 20 to percent by volume of diluent gas. Instead of the indirect heat exchange system described in Example I for initiating and maintaining the appropriate reaction temperature, a direct heat exchange system may be employed such as, for example,a mass of mercury through which the reactant gases are passed.

I claim:

1. A method for the stabilization with respect to vapor pressure of liquid reaction products of diborane and an olefin hydrocarbon having from 2 to 4 carbon atoms which comprises heating a reaction mixture consisting of such reaction products at to C. for from 10 to 40 minutes.

2. A method for the stabilization with respect to vapor pressure of liquid reaction products of diborane and propylene which comprises heating a reaction mixture consisting of such reaction products at 100 to 130 C. for from 10 to 40 minutes.

kalereneelCitedinthefileofthispatent Hurd: American Chemical Society Ioumal," vol, 70 (1948), page 2053. 

1. A METHOD FOR THE STABILIZATION WITH RESPECT TO VAPOR PRESSURE OF LIQUID REACTION PRODUCTS OF DIBORANE AND AN OLEFIN HYDROCARBON HAVING FROM 2 TO 4 CARBON ATOMS WHICH COMPRISES HEATING A REACTION MIXTURE CONSISTING OF SUCH REACTION PRODUCTS AT 100 TO 130*C. FOR FROM 10 TO 40 MINUTES. 